The Spring Security OTP plugin adds one-time password (OTP) functionality to applications using Spring Security. One-time password tokens can be used as an out-of-band second factor of authentication. This plugin supports transmitting OTP tokens via email and SMS text.
This wraps an existing AuthenticationProvider. The authentication request is delegated to the wrapped provider's authenticate() method and the Authentication token returned (e.g. a UsernamePasswordAuthenticationToken)by this embedded provider is subsequently wrapped in a PreOtpAuthenticationToken. This token contains the principal and details of the wrapped token, but does not expose its authorities.
If the embedded authentication provider authenticates the user successfully, the OtpGeneratingAuthenticationProvider will use its Tokenstore, LookupStrategy and SendStrategy to generate a one-time password token and attempt to send it to the user for entry on a subsequent form.
This listens on a preconfigured endpoint for an OTP token sent by the user (from an OTP entry form). If the user's token in the SecurityContext is a PreOtpAuthenticationToken, the filter will attempt to validate their OTP token from the input form against the Tokenstore. If successful, the embedded token in the PreOtpAuthenticationToken will be unwrapped and they will be redirected to the success URL. If unsuccessful, their token will be invalidated and they will be redirected to the failure URL.
Implementations of Tokenstore determine how OTP tokens are stored in the system (in memory, in a database, etc). Current implementations included are, LocalTokenstore (not recommended for production use), JdbcTokenstore, and RedisTokenstore. Custom implementations can be used for other scenarios, provided they conform to the Tokenstore contract.
Implementations of LookupStrategy are used to lookup user contact information. Information is returned as a String, and may consist of an email address, phone number, etc. Included implementations are LdapLookupStrategy and JdbcLookupStrategy.
Implementations of SendStrategy define how OTP tokens are sent to users once they are generated. Tokens may, for example, be sent to users over email or SMS text message. Included implementations are EmailSendStrategy and SmsSendStrategy.